FIG. 6 illustrates an example of a combustion system using a combustion controlling device that controls the operation of a combustion device (see, for example, Japanese Unexamined Patent Application Publication No. 2011-208921). A combustion system 100 includes combustion equipment 1, a combustion controlling device 2 (2B), a fuel flow channel 3, and an air flow channel 4.
The combustion equipment 1 includes a combustion chamber 5, a main burner 6 for heating an interior of the combustion chamber 5, a pilot burner 7 for igniting the main burner 6, an ignition device (IG) 8 for igniting the pilot burner 7, a flame detector 9 for detecting a flame intensity of the burner (the pilot burner 7 and the main burner 6), and a temperature sensor 10 for detecting a temperature in the combustion chamber 5.
The fuel flow channel 3 is a flow channel for supplying a fuel to the combustion equipment 1 and includes a main flow channel 3a to which the fuel is supplied from an outside, a first flow channel 3b and a second flow channel 3c which branch from the main flow channel 3a. The first flow channel 3b is connected to the main burner 6 and the second flow channel 3c is connected to the pilot burner 7. A gas pressure switch 15 is disposed in the main flow channel 3a, safety shutoff valves 11 and 12 are disposed in the first flow channel 3b, and safety shutoff valves 13 and 14 are disposed in the second flow channel 3c. 
One end of the air flow channel 4 is connected to a blower 16 and the other end of the air flow channel 4 is connected to the first flow channel 3b. An air discharged from the blower 16 is supplied to the main burner 6 through the first flow channel 3b together with a fuel (gas). A wind pressure switch (air flow switch) 17 and a damper 18 are installed in the air flow channel 4.
The combustion controlling device 2 (2B) receives a flame detection signal (a signal indicative of a flame intensity of the burner) from the flame detector 9 and a temperature detection signal from the temperature sensor 10, and outputs control signals to the safety shutoff valves 11 to 14, and the ignition device 8, the blower 16, the damper 18 and the like. As a result, the operation of a combustion device 19 whose components are enclosed by a one-dot chain line in the drawing is controlled according to the control signals.
Depending on the type of the combustion device 19, there are a type of eliminating the flame of the pilot burner 7 after ignition of the main burner 6, a type of continuing the flame of the pilot burner 7 even after the ignition of the main burner 6, and so on. In the former type, the flame detector 9 first detects the flame intensity of the pilot burner 7 and then detects the flame intensity of the main burner 6. In the latter type, the flame detector 9 detects the flame intensity of the pilot burner 7 and the main burner 6 together. There is also a type in which the pilot burner 7 is not provided and only the main burner 6 is provided. In the present specification, both of the pilot burner 7 and the main burner 6 are called burners, and the flame detected by the flame detector 9 is called a flame of the burner. FIG. 6 illustrates a type in which the flame of the pilot burner 7 is kept even after the ignition of the main burner 6, and the flame detector 9 detects the flames of the pilot burner 7 and the main burner 6 as the flames of the burners.
Further, the combustion controlling device 2 (2B) monitors the states of the gas pressure switch 15, the wind pressure switch 17, the flame detector 9 and the like, closes the safety shutoff valves 11 to 14 when detecting an abnormality, blocks the supply of the fuel to the burners, and enters a lockout state (see, for example, Japanese Utility Model Registration No. 61-19331).
In the combustion system 100, when the combustion controlling device 2 (2B) enters the lockout state, the lockout state cannot be released by turning on a power again or the like, and the operation of a reset switch is required (see, for example, Japanese Unexamined Patent Application Publication No. 2011-215960).
In the combustion system 100, a reset method A or a reset method B described below is employed as a method of operating the reset switch (reset operation).
[Reset Method A]
No restriction is imposed on the reset operation, and the reset operation is set to be enabled.
[Reset Method B]
After the reset operation has been performed, the reset operation is disabled for a certain time.